Dengue fever is an acute infectious disease caused by dengue virus, and is one of the most widely spread mosquito-borne infectious diseases in the world. The clinical and laboratory characteristics of dengue fever in China differ greatly from those reported in endemic areas abroad, and most of the patients are adults, and most of the severe cases are elderly people with underlying diseases. In order to standardize the diagnosis, treatment and prevention of dengue fever, the Society of Infectious Diseases, the Society of Tropical Diseases and Parasites of the Chinese Medical Association and the Emergency Medicine Branch of the Chinese Society of Traditional Chinese Medicine (CCM), based on the latest evidence of evidence-based medicine at home and abroad, the 2009 World Health Organization (WHO) "Guidelines for the diagnosis and control of dengue fever", the 2014 "Guidelines for the diagnosis and treatment of dengue fever" promulgated by the National Health and Family Planning Commission and the In 2018, we organized relevant experts in China to develop the "Clinical Diagnosis and Treatment Guidelines for Dengue Fever in China" (hereinafter referred to as this guideline).

This guideline aims to help clinicians make rational decisions in the diagnosis and treatment of dengue fever, but it is not a mandatory standard and cannot cover or solve all problems in the diagnosis, treatment and management of dengue fever. Therefore, clinicians should develop reasonable treatment plans based on their professional knowledge, clinical experience and available medical resources when dealing with specific patients.

Epidemiology
Patients with dengue fever, latently infected individuals, and non-human primates with the virus are the main infectious agents of dengue fever. Dengue fever is mainly transmitted by the bite of Aedes aegypti mosquito, which sucks blood. In China, the main vectors are Aedes albopictus and Aedes aegypti. The human population is generally susceptible, and some people become sick after infection. After infection with dengue virus, the human body will have lasting immunity to the same type of virus, but can not form effective protection against different types of virus infection. Re-infection with a different type of dengue virus triggers an increase in non-neutralizing cross-reactive antibodies, causing ADE, which is an important mechanism causing the development of severe dengue fever and is one of the major obstacles in the development of a dengue vaccine.

Prevention
The main preventive measures for dengue fever are mosquito prevention and control, cutting off the transmission route, such as killing adult mosquitoes, removing breeding sites of Aedes aegypti, personal protection, wearing long-sleeved clothing and pants, using mosquito repellents, etc. It is especially important to detect patients early (especially those within 5 d of onset) and implement mosquito-proof isolation measures for patients. At present, there is no vaccine available for dengue fever in China.


Pathogenesis
Dengue virus is the causative agent of dengue fever and is divided into 4 serotypes (DENV-1, DENV-2, DENV-3 and DENV-4) according to their antigenic properties, each of which can cause dengue fever and severe dengue fever. Dengue viruses belong to the Flavivirus family (Flavivirade). Members of the Flavivirus genus also include important human pathogens such as yellow fever virus, West Nile virus, Zika virus, encephalitis B virus, tick-borne encephalitis virus, and St. Louis encephalitis virus.

Pathogenesis
Dengue viruses enter the human body through the bite of Aedes aegypti mosquitoes, proliferate in the monocyte-phagocyte system and enter the blood circulation to form the first viremia, then localize in the reticuloendothelial system and lymphoid tissue, replicate to a certain extent in peripheral blood mononuclear cells, macrophages in tissues and Kupffer cells in the liver, and enter the blood circulation again to cause the second viremia.


The incubation period of dengue fever is generally 1 to 14 d, with most 5 to 9 d.
Dengue fever is a systemic disease with complex and varied clinical manifestations. The typical course of dengue fever is divided into 3 phases, namely the febrile phase, the extreme phase and the recovery phase. According to the severity of the disease, dengue fever is divided into two clinical types: ordinary dengue fever and severe dengue fever. Most patients present with common dengue fever, which can have only febrile and recovery phases, and only a few patients develop severe dengue fever.